1 research outputs found
A mixed distribution to fix the threshold for Peak-Over-Threshold wave height estimation
Modelling extreme values distributions, such as wave height time series where the higher waves are
much less frequent than the lower ones, has been tackled from the point of view of the Peak-OverThreshold (POT) methodologies, where modelling is based on those values higher than a threshold.
This threshold is usually predefned by the user, while the rest of values are ignored. In this paper,
we propose a new method to estimate the distribution of the complete time series, including both
extreme and regular values. This methodology assumes that extreme values time series can be
modelled by a normal distribution in a combination of a uniform one. The resulting theoretical
distribution is then used to fx the threshold for the POT methodology. The methodology is tested
in nine real-world time series collected in the Gulf of Alaska, Puerto Rico and Gibraltar (Spain), which
are provided by the National Data Buoy Center (USA) and Puertos del Estado (Spain). By using the
Kolmogorov-Smirnov statistical test, the results confrm that the time series can be modelled with
this type of mixed distribution. Based on this, the return values and the confdence intervals for wave
height in diferent periods of time are also calculated